The present invention pertains to vibratory plows useful in laying of underground pipe or electrical cable, and in particular to such a machine having an advantageous combination of features not found in previous vibratory plow machines known to the applicants. This type of machine uses a vibrating blade to make a cut through the ground, through which cut a pipe or cable is pulled and laid behind the advancing blade, without the need for digging a trench from which the soil is removed.
There are numerous applications in which it is necessary to lay underground water pipe or electrical cable, including, for example, the installation of sprinkler systems and cable TV systems. In many residential neighborhoods it is desirable, or even required by neighborhood building restrictions, to have all electrical power and cable TV cable installed underground. It is desirable for such applications, to have a self-powered machine which is capable of inserting the pipe or cable within the ground, without the labor-intensive, expensive and slower alternative of trench digging.
In such applications it is sometimes necessary to have such a machine which can also pull auxiliary plows, which are capable of laying auxiliary lines of pipe or cable, branching off from the main line. And it is desirable to have such a machine which can pull and lay the main line of pipe or cable, and any auxiliary plows and lines, in the same operation. In some such operations, very large pulling power may be required, in order for the main plow to be able to speedily pull all of the pipe or cable line material, and any auxiliary plows, as well as overcoming the soil resistance, which may be quite considerable in hard ground. Although such objectives could be accomplished by use of a main plow machine which is not only adequately powered, but also large and massive, as has sometimes been done in the past, it is desirable to have such a machine which is able to accomplish these objectives, while yet being relatively small and light weight. Use of a relatively small machine facilitates working in close quarters, which is sometimes necessary, particularly in some residential operations. And use of a relatively light weight plow machine is more conducive to minimizing landscape damage, and to ease of loading and unloading the machine on a vehicle for transporting the machine to and from a job site.
Depending upon the soil conditions, as well as on the total weight of pipe or cable and any auxiliary plows being pulled by the main plow machine during the pipe or cable laying operation, both of which may vary considerably from one such project to another, it is also desirable to provide such a machine which is capable of providing not only a linear oscillation motion to the plow blade, but also provides the option of providing an elliptical motion instead, so as to provide greater flexibility for the operator in dealing with all such varied conditions which may be encountered in different projects of this type.
Although the documents exhibited with applicants' information disclosure statement disclose prior machines having particular elements or features which are the same or similar to particular elements of applicants' invention, the applicants' invention accomplishes the purposes and provides the advantages discussed above, by providing the following combination of elements not disclosed in any prior plow machine known to applicants: a V-shaped plow blade configuration; a winch which may be secured to a fixed object ahead of the machine, for provision of greater pulling power, obviating any need for a large, massive plow machine; and a blade oscillator having the capability of allowing the operator to select either linear or elliptical motion for the blade oscillation.